At least the Portland Oregon police had no such delusions when they were interviewed during a Ceasefire buy. They said, "no matter how much someone might wish that crime guns will be turned in, it just is not going to happen."
This was while out on the street, several Oregon gun owners were adding to their collections by offering more for the guns that were being turned in than Ceasefire was. The Portland police did not bother them, and also told the new reporter, no, what they are doing on that sidewalk is totally legal.
BTW: for those that do not know: Portland, Oregon is one of the most anti-gun cities if not the most anti-gun, in Oregon.
$150 gift card to a grocery store?! What a load of crap, this might work better in the inner cities I think. I am thinking more along the line of fair market value would work better, then again still don't see a better outcome even then for them at this point.